SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '11be4367413fa543c022655015fd2a707a36ecbca22100454c03ee15f06e4f1c' 
  AND token = '2XCDyDL6K5wHJZZiCSACk201NJvoSIqD+L12orXSyq8=' 
  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"
    }
  }
}