SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '17db38bc134be66ec27e0f4127a6cf42254e0dbcbece801127dbedc1aa033214' 
  AND token = 'EcLQQBX4NM6tUvV+0pGjmBnVmMcQtZ1mQeSFWgXxAHA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}