SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8bd14916ef35cbf67ae5b4d0d5cde5bb0b640ca17332199649dd309615cb3096' 
  AND token = 'jyhfu0dXg+DiMjFaloZSZ2XJZV3RQiJOjfew5eCpc54=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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