SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '642bb7c416ba79838b721f82343c83038dd2749549c489629da65f7ce8d5defb' 
  AND token = '58vVudO6d6veWWBbKOfgloahoFse8btEi1fwXcA9qT0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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