SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6fec842c17c6d424db3dcaef90de502b5c537a75f9fc6a583e19913d74ac7bd2' 
  AND token = 'NCy/EzvxG0myPmOVNgrnJVSkUB/gUyHOatfAKXHizM8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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