SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '401f4c950eabf23851fd8c034b5e5aea2d6e308baf8856b3d4279a9692820b19' 
  AND token = 'qIOev1mZhPqU+bN6eJymThBnrWoo+zL5JZClb5KhloA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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