SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b446813e7d2b4d2a97d251f959591d050acf76074e486fcc5841f8fd582304b2' 
  AND token = 'UejyX+ImOSvz6SPUV+bjfEXZ5XbgO+m9ewie/XOu+4Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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