SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ba3ab0e958c7f216653e5bc1d2fbcb966f463ae662018db26058eea03d5c2206' 
  AND token = 'UHg6CBoBD95zzA0wXnP0gZez6l6CBHT83tj0+crXTBM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00062

JSON explain

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