SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a91de5fc4d9b851158fd1ae74d71b249e7301ef41f675521b462405a8bcb8c3' 
  AND token = 'mW72AKkYUxHJbiT9trv6lxiDyzTnJjNbPdZ/VCSXyzU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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