SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'a23965676a671925cd4c9dffba8d2037d2b7ef99f043cbd524006e9ef880c366' 
  AND token = 'Ezfa014UTM1bS2YXATmUivg93fTUsxl1IyXIyEhLtTo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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