SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd47b607e365f5b4b4ef72f4e95974887f6ad6a618c5f3cf218c30e9d4759115a' 
  AND token = '1gQ/lGWaOfDGlcG4sUE8RvEkUnE+OQIbluh/70hzcHo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00062

JSON explain

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