SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c386396b4236ca641faa9f2e8c92973b97ef8a1d45aeb9eab6dc6de079a5221d' 
  AND token = '6aUYTLkWyqjdXVOLjc+PxtG6WFC5PWvkZYuPdUwzw2w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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