SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a66d3e8e0e54cec955dc31211c3775255d11c32c368038f9a7eb912abedb1d8' 
  AND token = 'TCY7lKgfOIM91nNoNNno0yQQTKj5rj/s6DAlJE1QAS4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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