SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '3d1e8e601dd3aa6b44f9d6814d16239aa977cf62457466d9d807c865f974bd6e' 
  AND token = 'hZf/jys7dg+OWlq6ipP6uGwxSNcYjPY/j3XBZ2ft4LM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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