SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7746aa19b4d80284118233b874074771216e0138c05254ea0b8f4353438e06ad' 
  AND token = 'hU/0DbAsYxRUjbS86MwBtOyD5L86Cso+/pyIDA9iWzs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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