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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe950e0c84d5e636c6f2d8423ffa1cb217dba70fea6c6fe16342e9e9df6f0b76' 
  AND token = 'zxPqFKL2PT4OFNDPmnc7NVu1zhGRV1GGfDSRPxW7Ps0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}