SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2e742e455e96594ac1cccb738460ab60578ee28d83417bacc481a42ac15777b1' 
  AND token = 'krkHE3cveu7RZzDf6GnmWKm2P7f4UDn3ufvE65uYTXI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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