SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'd3d89dca13bcd272a0e143ec528111750797092379edc71a151104a2e86763ba' 
  AND token = 'Xukgv8jRhmGVjQvvNp21NxF30AqmZlU8ikg788rKTuM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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