SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '343922d40ca84891f09c5cd08de41663dfd908545fac2f69a02418d7e1ff04e6' 
  AND token = 'SLKV5KZvWaL2cNU16fvFRk1v4HUyy7O/YNlKgVG+B0k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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