SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0b46b8b3816ca936ab40236fb84c402cf68ef7c5fdd161d53931feee6aa56f32' 
  AND token = 'WxS+3i6pw/i2xpUl14VAa1Vn+12NuFiaboN9M+3QHvM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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