SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '4cda509e3a1bb66794c6041a3fcc1ffef367bd42f4d090e259c5054838f9f99b' 
  AND token = 'gXnjKBDSmgoLvGEhe/VRxzolbUai6U9Y1fjj4J2HUgc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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