SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a492349346f847fdbde38228c412b85b2465558ae4e121533de79498626e355a' 
  AND token = 'IxuomCL/DrKYGO+auxpGHN2WqISPLvFR+iKZCMz8qOI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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