SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad5f2e06da5bc88b734bbc45630f43a807244ce761b77bbfaab7dddad49e05a5' 
  AND token = 'KQ8DH+R+9XQsw1ePiedQEKFVwUOidolrlPRdJR/HxjI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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