Sandbox

SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a50750f555d88fa870d5ac7271aed5fbc8633c74dc739e68848e40fbe14b9f7c' 
  AND token = 'KmHYF3qCe7AtTXIFTKGt7zL/nTBMt3AlTK1OvvNds5g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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