SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2bf08f53dc42cf7c103ad67a15f4c1fb157cb890f63b19eba07e9ea5c80912f9' 
  AND token = 'P/rvA/OdNcKeQGi8EwsD+Fa3cs4UdfrHj/Ox8bQLpHc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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