SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d75b8b21c60997070b949552bd6d97f301b119986ba90624f657d0a4d40d8cd' 
  AND token = '/7kAhdgNUTjhz/j3IQZqLpxNq1f7DZBALNKHwMY0UOc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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