SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e3ffd982ab5fabe90c7df8e0684bd17a37d82a3b4f7a22f791494c53069021a' 
  AND token = 'zd1gvieJOTq+WEBzqy/DIMqUXu3Sgftq62JkYYx2ebY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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