SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78a1538467c8371f9b1ad51f3412476c7857b0385acb472c84c88627207a7307' 
  AND token = 'HjTTqZDuzNmNVI2eD8H+9H7jHKGJRs578+a3d8Cmpik=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}