SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9be71867ddd375b6013cc0f79dc865c6058acfc748bd10cbc4928eca84b2f05' 
  AND token = 'U0PTIGCItO07uz6QRhzgXaKyIg6CFlrGJX6L3qYlWKs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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