SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7a63fc6493116333eeed475524bc6494011d36cf6e300db645a4c18a795a56b' 
  AND token = 'XKS0eFZ2iCfWcRK5iXNQkOkp1PWiVOUIzA7FXUfPQ00=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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