SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fd9ed6a7ccb201660be81f948e298a43d55cb5b6bed5c4671c83434c11777027' 
  AND token = 'tmFh88a/Qn1IqGyIAxBwB4uLoJObs47iWfzCV3Twuvg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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