SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d6500f31d069157c02754e5f0e948c1ab559793e5a9232df187804699b36c0c' 
  AND token = 'ljpgQmllbAg6/1aU3rwzQ+VCFmGzyxGnWnlx8XqT+/A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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