SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9db08364d6122b994029ce21b9e558f8c3629e878afcc28f4fb8187f1e7e9aa' 
  AND token = 'CsvYO+LEBown2BMlseWAmNx8a7ctE1Yz0tvQ2+xY2to=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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