SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e8343d312b7d774c62496b7ae6e32b8d84cf8c2a5295cc07a230719cedcc284' 
  AND token = 'xw1VYqNdJnACfyYDOdw9QRnjkz9xokUPhXPoBZktGaU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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