SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '137d6b5220e040515666c2aab3046cd6e8feca91c323e7fff8baf962193f255a' 
  AND token = 'tkQvE0YqndVAWL0xYzNI87gWM+gjy6IQy8r7yJ9kYdw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}