SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b3aa38a861c7a988db893396168b9f0cd65e980e4bf0b358ba3b0f8bc726dc1d' 
  AND token = 'lZlgjkt7Q6rzTHSOka8YTEDsFIkE8BhT7YLuVVEKBnw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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