SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '16612fdedc2ada9117a93a6917552e8d742ea5085ec2704db38515e5f9c47141' 
  AND token = 'BX519l1WQGgnASLTvXc8BWO5/UUH0BidZ3tIZi1RiGg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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