SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '5b46b703cc25a6eb48773943e41d652669098f570b3eb6c350f7b4435c3f21d1' 
  AND token = 'sBhXQKbvCP5kJRn63QLwFO1eAYz0niqR21aRIEvb4VM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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