SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '17c7200dea341810745bdd21c67621d4a2c27882927728c050e80ac77080ce7d' 
  AND token = '2sPBlru0YmkTAWJ1PupDH1XriJ43i9y0tgmh9svZKus=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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