SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '8e4110a63699bc3a4bc7873b4b655b65522139121c4064d00349fddcd0fcdbc0' 
  AND token = 'unXSpHiCEC+oa0XIMnT32xfUje5kju8gMr5xLxGn/jU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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