SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2fddedca105a56d8320b17851228f425717ef3bf0b07a6e12266e80d90fd96f6' 
  AND token = '+jSMumHZCkUtHOVviEPpliAwtt5HThZoAJicDhEToW0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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