SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c1e767d0e4d81348d61a3fbb01a5f0fc3760d9d3ec3f09a4a1bdb2ff9ceea05' 
  AND token = 'I+5XFKp2Au7qvLGhc0x71liMm9mjT8SUxh+s/qCBOjc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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