SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '916f984cc9be61061f7c00924d49321ce451f3db5dcdea3cd252fe1298761825' 
  AND token = 'w07tEtjz154xChJsehNyi7QSoz4VInQ9HFhIBh+3+tI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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