SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a22780b986518db148777b4add91620c692cc13ebf44258e5563ef870d244523' 
  AND token = 'SszFFDmnBYtnfk2JCHbxMu8rIocn3f6LliNgK7ewxKE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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