SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac03985d9fc270a08450ef3b69b02aca8fa4e3397f99099dfb65018548531679' 
  AND token = '8bZzCPpo+knF5ZWG5p0Kx0NQ+yqVApOwJ/XZ2bIqBSg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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