SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e39cf35125c9e41dd888310efdd0183551b1073a56f75b1e78e0b5035db7fff9' 
  AND token = 'g4u5IpGzI4zJJusr4EJ8BIFCIVDUBVexaeDO734mlz8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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