SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '23a818cfc979d40626186afab80cccd7f8c40e34f18322b1b53a4f6d79eed775' 
  AND token = 'L1w2LqM7fukWcWhHR/9epED0Q9madnXlOiLke2odxQg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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