SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a1a114c0dd829fea231af5bf0c6744d53ce3d471ebaa40fea987f848e94f124' 
  AND token = 'DVyBirWdzru8VXVQJ7ytrhThUzAqVHliBQp/8hPOhR8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}