SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '034d3f092f4b8f2eb3d4a3e4817ef99d649c3122d760485d1f571f0e520d4374' 
  AND token = 'g2SdG1suP1HEHpXO+HEAYANycuQp0SOB4Wdm8tAPzDg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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