SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8744bff8cc88ea8544512368ba3d6e35f18fab9f84928ab1623555a2ee3f211' 
  AND token = 'ZiZy9XZRBrMxXEG0J7vtKGw2qu/RnuUePYR7OGTSFhQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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