SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91dc8c94e6dfdd6a647401d987fbec03a1a654f1b73a33ee16525ac8b175d518' 
  AND token = 'JYFICKhAfLjpfcdyM39eL8YA/IixTQOhxke5zVYpdZc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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