SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd5f66edcecfa16ac6b6eb12b730042b3fd25a98724178af23d9bc19b2a5738e8' 
  AND token = 'p7DwJsuIG7ojg2JJRveFsDGSPtzE5/czG1NQ7KD1qnk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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