SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f2bc4ca842563d49f0904d271078ef6b02f3208103b0478ba4f75b21917e657' 
  AND token = 'dnaSydSDV5CJw62lVDrDrBCmLL64WjFWPjMibijOL9k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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