SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5f99393c97dcfd08e8160c8cc0624b4f086147bba37231a9cb5aea82a980bfd' 
  AND token = 'ObNcUkWlYFldDhNS1MvJMwe3ll318lPHcXwrD0q/DPc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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