SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4fa97bb6889225fb0774f544199c380f2b646e9240e0fd52763b01618e215b6f' 
  AND token = 'S7dnRfXnIgXDfDb+gsUon0rFBjtu+Pf7Or7/JdYWNzE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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