SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d03a9e726a5583d22c423a3444efda94abe337926df5ff969a67926004940d6' 
  AND token = '3R1bGim/xTtkuV2LICqbO1pOrakx9V/ILPS4kndEdEI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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