SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c852830ca7e807f849d38c6ae6b1fc73ea2cf669e04a7e0c1591f1b2f96bc0f4' 
  AND token = 'UZGh8v643G8Q7bVdRgpgwULNleJlyzl7QHnK8wKRBEk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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