SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '7490fa21e784ea65cb36ea1b6e5a99b3c2ef4f23202a86c02a64e57dd8daf942' 
  AND token = 'mhUzYpe28KKyJvhop1tSo5Kmbm1QV3ZqsWSoM9M3hwg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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