SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b81ebe0ec2033c57434c637121300c2452a36632d23ad2d6a603897a9635bf92' 
  AND token = 'ZCuelVI49BYzduHs7qblo2jN6S69Em4EV1IHu1UBHbc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}