SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a1375ca54dc123804e9237c15e0abc79768abaf22bf55fe3e2492d9f098026c9' 
  AND token = 'u0QYsVsznk2WIiLjwkfykWEyECg606cocKhM+XAvQEI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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