SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c0f4adb592e31bbac60bbfbe78111f210c2f51d8e86155ab385864edd805b21' 
  AND token = 'DojkiH5O9ysi1WHDXROH1swIZerVADcil0NmMEbOdmU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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