SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b085d04aa1f68ef98952f114fa22a986032e790e3d1c31719c85450a57a6a4e7' 
  AND token = 'AAIDjQolVzAqLUdMsiHGoQjBIkFF0rjIbTdIEumGTfQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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