SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8603f863d8120b8bc510199fd1168a4125004ab0e5051d9cf73f7d21d13f8db0' 
  AND token = 'HGP0mgEDA8vhf7k2GQYAsWegfEIO8kFsMz7vvzm4UxQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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