SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb6ec425b5a6139f8c4f12f73b5f3839629728e9c97dd55aa4f21e35e990b7c7' 
  AND token = '9OE9JSpaGr6J/d+huzUqwzQuSmnDP4gSoZso7MCqdHE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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