SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5391f80a83f4cc4a94bc704465d54b061e6ba79aab1548fc643a1e3e8925cc4d' 
  AND token = '/sHXCCXgHSyqV31I1kHypbUfHMtx+RLCiSvw126eqiU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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