SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b6c46353e8e2eac6f83b445226604e2b4e266fdcf64b4d3b894441f5f53dea14' 
  AND token = 'PLzzZEbRAAxeO7B3/lpGIUOg2xObwisn7eni1y7bbOQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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