SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd2d564d10099f2d1586140364796f689f47dcd81317fa06de5b51986d962a82' 
  AND token = 'qwKLVwHo6//ppsoVrBXCMYJdCAYNtFMWb21ucp8OZVw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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