SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78782007506b9a8d6d37268d2e52fc7d94e0ccfed2f21d219affe437d6ae01fc' 
  AND token = '8YsLVSba1lSqOGsJwFsKOhcSuiDxBOhlxG+yiJ86VIg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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