SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8738d90dbadb5714172219e89d6fc51311a16defb64bff00f8fb84a03a67847' 
  AND token = 'dhhy0me9RXPxpAg0lIpqQvBiaiJC+3Xe3lUro+Oe/mE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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