SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '160610b4cdeca3916daeee946a5c775cb910d9cdf755f21b815c42826dcf8d8e' 
  AND token = 'aMN2GqEz6eqZMd0V9lPk9bBDETurMS9RKuuTfTk7/Sg=' 
  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"
    }
  }
}