SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dff2dc36dbea2f16a1ad9ac68dc12be94acaafb5d595185b188db6c3db96ac2e' 
  AND token = 'EnfAwQVg/cICPm9KJKAj68LVcTNKua2QG3H29q8Bkao=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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