SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0f5d8738ed030db6f48956cf182fe04bc409b08a7d18471351311a9e7ba1a85d' 
  AND token = 'fuQcqGeyBRO8jRLye5E7scPBmFTVH/FfYi5suCp4f/g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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