SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5712593186de4bc12005084cc1f2afcdcb350db398c5ffe022bb13e88130f8b5' 
  AND token = 'onMyiYeryCURd3ePYPPOWWDsMZnTFDj77DC7n2HlflQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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