SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79541f868b3a019b7bfa674b6f44d94deed9bf52466d5cc1f5773f45857b164f' 
  AND token = 'KyYj4l5k4+I3t55ZLLY07TuuHSSa52c8Uz9OZWUD2sQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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