SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '61471a55498edcd482b9801cd140e96cb189ee99e761be2fa96fc7f53b326c94' 
  AND token = '+LQ/xlBvCC2M/DonJog7hZGOnV87M1KSsS7RSszfyck=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}