SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3bef81103b9be80aae1b20e92a4fd3da9642c5c1bb2916aebbc91c4496d5f8a9' 
  AND token = 'nRmiPoErXdr7HM4IBTZDJ67j5w0q/UxnJCqxllKF4Ws=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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