SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f044d23cf1ff39cf5c07693df82690f9a595fa7e9379d2823525cc39af035939' 
  AND token = 'HmBxxJBIjLawCn4sbruPQOseaVRwcToe9Qayk+UydNw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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