SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'fd52515ab0043d67da7e43e32dfa31ab4cbfbd33e8501d1a40e4635b5d928bc9' 
  AND token = '8UNCG2dU1bFiKhznZZSvz2tHnXdnw/W5giajljATB2k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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