SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '9558b39d5d8f2862a2730c4084c41bd02aadc7388d9b1263b1516af25167e0f9' 
  AND token = 'L28/Pz3GYc5uEwLU4AehEqRyWrQMWmOjRw4GdT+PjII=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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