SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd55fc3734796fe4ec41ee57152d3357985a9d067380538ec6ba1aea6a7499f9d' 
  AND token = 'qwCA+f+hxOwvdjMgjjxwuFycazalvpYFhoUv31T7aqw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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