SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a41f3065991edf80d8875985ad813cd921434140bcdc62d2377308c76ce17a9d' 
  AND token = 'DclySeeClWh0VAVMKdFVAQ13fOKvSIxFMvmozmHx+jg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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