SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '335a5019da3971a11b27ddcf1df25e8b4b4842b97f14a4ea35804b6e6cd05551' 
  AND token = '9Ckp5hD9k+MfGvg9ecj9bqzg4OxEmCjjzsPhCo+e/bk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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