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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c851903d093e10061f25b45f9d020ebf79b352df2a3acd3cb9083cc7afcadb0b' 
  AND token = 'RNSRkaXQWtU3e9cQTlhf51YAczj2eZjQMF9jNf5CX14=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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