SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e821b991443de1f2d396e09d761ac5b1c17fc59754d36a6a13010b4f51b50091' 
  AND token = 'V2uQHTKFGCYxMe8PS6Y4MW9/gXM2gpmbHMQbkj4rz6o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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