SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '571d60304ffe93ff44c03fb57a7e22e1ea6e91ec5c6bbde7085762b740a076c7' 
  AND token = 'jn/gvohKzimsipZhxnopXxNVYFhPPBLhbOT7x9radUE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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