SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '15850a1d8a0ef37a76c6e6306a25b91b77909bd8a86c849da8c3f1356264bdfd' 
  AND token = 'lRK/ChsPjndVgnLKuCzU/an7NDaaHYY8NB5geNpp+Y0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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