SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23d8b64a3ab2cd8cb19874d77174390a1e12e90f2df91e850664f50d720be38f' 
  AND token = '1i+60rNQTS6TNhtY1FjGBysZBpVQtv5dDvLFhydVfLA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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