SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '76d18133429c092a1f0a967fa151260464a853c8d5a96f15eac7abc89ec8c43d' 
  AND token = '9Etd8CGoHVK5A1FyyJIAwJrzYPafuqGMJJYMDPF08Vc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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