SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'acb5fb2304431f8f105bd91d8ed64ff9da2f2f21ef872340e5fc29257f4881ed' 
  AND token = 'gkYqzgvtCgusxFB2kfdQSm6cTKryNxarRUeEGtTa1ms=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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