SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb1837c279076049613acbef8703a8d962ef36ea733b3078bd9b05ea2be0af3f' 
  AND token = 'kWPOAgFMZToopow0CCq8F6iqdIsfIx4OvTO0bIi1x4o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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