SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '684881c710424c97585292d0e48eba25daec073c450ac4d71c4f9f8ab264e4ca' 
  AND token = 'euXj6VA7V/YBEXfjFMcDrjoaTJR6BGmHq1wXdj4d2Z0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00084

JSON explain

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