SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2df631bee6b9a038743a325aa717dd492bebb8b9428659afc96fbf495a01db12' 
  AND token = 'Z4PBSZnUx4/Fq0/MVuw2qHrldkmodVevHfODidWmlkI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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