SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83c45da42dba1655cf131994fdfc867efa186f99b881208fb9eb067caafe6d59' 
  AND token = 'PwFzCIaMWk7hG5WlF6HnKkhbagXtdIaPtTaPZpMpgCg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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