SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9d0e5014125203dcd95d899a57780209a40fe40994cf92ec8bbb6eda1dde20e' 
  AND token = 'MIVuOjwSxRcA6Oifujuq0vsD1IqKdQCBo7dymYz+Hsw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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