SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '40c2ce47ed62ed50f4de998e3f6f363f508936cad6635303e6587fa0d9bbcb29' 
  AND token = 'eD3fR+R08OIJmQZUU14DlYqZ7LMGSu73MJQA3AaBHUU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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