SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce7e67f1c48aa12396768a85a7c39c1ce05a8754b674537d66146b50a79201f3' 
  AND token = 'hRY58/wQa+brgFDZuGyYB6drJXyrYJpGURyNOhvMUE8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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