SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '731a41e784c35af1b2736edfbf4d4718886313ee96d058300670ff4e28708c57' 
  AND token = 'fVr/+Wh+ZJto+OGB+HkfL53AkgEqsDYW3X9q/fKowgA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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