SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a863e02e3ee467dea88571544f151e98d52801ed1c7a71f84638c60b37560781' 
  AND token = 'NxnSxjTNQWUHU3ZoXJMyzU8fTnJ1zqEbJUKnngWwUUY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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