SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd67a792d47f1bd4422d04afde116a8e809f7b179b9b65caab484795e4aece72' 
  AND token = 'TSYkW4auIgSrVLKZAEFZjk5QhhSKE3l+yX9zkA3Km9A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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