SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9a1d1547ed32cce7314e98050857a5da8570e3522018674b32d1f96bb783862' 
  AND token = 'LgxA1cbkr2CR1RxBlO+qn+Ag4QQbV/smkjl5S4iebGU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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