SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '4a8d68c9bdb65661aa0b59c77de6c1dbb887a39fdafa34364e62615e5942bf79' 
  AND token = '21tF7aX1erQRMqVG+Cqq7+PaOsCZ8hNv2OeUJPHvz2I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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