SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4fb69bd192e674be2344d17e565ec632369e773396f296a864dc0cefdfc0e446' 
  AND token = '/dWPML848cpEZqSHtlFHmVXSFRQkRSOVsZyJPvcfpdU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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