SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1cfa3dc5ced5222645e8d16cef6de3fe28941478ffc285a8bca91f5560c46ad4' 
  AND token = 'L4g5HNON5FDJNDyAB6RSQuvyrveKRioQWoYGXvf4Q6c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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