SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '43369b7912d16717296b09f141b561cc5aa2a09624468ca9966bd85757ede9f7' 
  AND token = 'pfDF7pu0PAOn0wWuVMY4xGkauTmTk2qVvNoqzUwXUCQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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