SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b91cf6d130cf04cf5670b5f83a22f411a7d5702805f9ef721ebc601d87f91826' 
  AND token = 'FO3iexQbyjdjCKvnzZWD0oXMlSjB0DXYoWlk2oPDmNc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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