SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c7ad24bfdf5aa11a3687598cfe6898da20ab036978485c34a8c567963ac69eb' 
  AND token = 'WinETvN0W9j4+oLVYHeFT7C7oU//6zNw/brFLmHCqPY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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