SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '2dbd2766d9df0b5a038d39289e9e857fefe1708d4b001be8ac960d6c8f373bd6' 
  AND token = 'l2h47ITWWqkFq9uP3StRm/OtN3BGCubibD3zGgETRLg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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