SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '8a56b23c9bd1d5c900aebc666639521bc00a36750475a34ca91675a6d60428c5' 
  AND token = '/CyehLda6oM5G+DdBTpZKdBvOF1k/0W29CZ85bc/GXU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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