SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2d3b2578251ed2561a36eb517998dde28f25ba161638e7ab37765ee2a19307e3' 
  AND token = 'usDKZJw+HUjiKbPlBzc1DqghW+J6fTw3oeP3R/WS6oc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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