SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f06b36b54aa000fb44ae22309aefc9cd83d99a7b2fa22a6b4b93dc8f992df5f' 
  AND token = 'hDWgRxsMNTvW/WJa6LUwdTMGnNx7pO+a03hEGfVPAv4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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