SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a190eba654a30b9a24a5697549b8c2e576033404971144cb7be1183784f5def6' 
  AND token = 'HWZmWnDWtqQvYxOs/mmPyU85jYXsjniVX35LErlQfTw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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