SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1420f1bc1b7334db01b135fcbb60b9d6c5db90ff2579243737b5c6cd27e4bcd6' 
  AND token = 'wsda5CLhmFJYToP7bru3bqbk+fbJwPYVgSmNVnpMnbk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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