SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b3f6a66caa2ec7c3b8b9467a7910b1ae59a474fc151ace93386cb309f3ed175' 
  AND token = 'BhRTaMCJbOWQtX1qzGq+N5rw5BsgaZP1A3g7E22K5Ck=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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