SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bdc54726d2675589b0ea83405d34721903f51660e96282d458bd9bca30e65b49' 
  AND token = 'vFprWIGu+LrENioVIA4Skrhs9/dOywd6P12pZQ7pE34=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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