SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '142ebda010054891c381a5df7595edf0d357f19da4cf53cff85ae164d3f17ea6' 
  AND token = 'lfQwiw6sZZorlHaHMqxI9nH/U2EEIh9HHMIguFuT4LE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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