SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3960c2c50f2e244f41f14d8be88a8ade7b93414a5db6efa59c2a10e67497760e' 
  AND token = 'wU/cyu4OUniThUA2Wt033vb2do/kmvTmwmzBPJMWZVo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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