SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd599d63576c5be8bda4f453c016d79a6951cb0309a7831836880a5207599a49d' 
  AND token = 'CBnZY50T0m1BrS+tDvM9iOskLzs+mvFXYCUd66mCeJc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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