SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b0bf1a74d0f667d817fc9515736deb6afb0636113461300545d3c158926c9d3' 
  AND token = 'x9J/mkkv+zxkKs8ngz7LrZU17xB/GIpqJOByqVwDwO8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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