SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6fe161523aadad90f0d6c980e1267caf8bf64ef09875b4bc7d1cde78e556b59a' 
  AND token = 'sLe2VxLm+nwV2paUBf1bAx3WjWWjQkVQaLu5ooQzOFA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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