SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78b8f2cd52c52452c736d2ec9e9bf2cffeb5e152dad588f6cc7ba7377511d6b2' 
  AND token = 'f4iONXKvUClo7+7SmI/cQKHUYDmKR4GjRrqj8Hg2gLw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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