SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0048a366550a4233f718802c2a3c64b0a670608b2146dda43cbcf29526fc0dbb' 
  AND token = '8hkzdHSRsgfzI80AxSHxszYIgSOvxHBPX3Fnt8OgQrY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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