SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'b60b48d7afde89fc212f09448a6003bf0754fe02a6a5b839996e16d96cdb919c' 
  AND token = '8pItqQ4ANZZOB+oxHjF4wfvueD8Vl16aiRACyZGFtrE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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