SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf273f77c0f0705381d2f8816f4b662d53e92f619a258300f7b5abfeaa167739' 
  AND token = 'DcTqpVa8ZWCqOQBVkswvILg67dZ5iqXNEx0whsmp89w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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