SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '48913e36bc1f82a7cb8ad29501ba71c21c957162166825a541d53d94608998d8' 
  AND token = 'mDhhjJfoq6HoFUtZfzjIUwzAVr6SSdkr+WO0VLi7Edo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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