SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '194d1ab74db0640edb06218e817ea6e3acaab7bdb3eac48021f6b6218c3b6a7a' 
  AND token = 'U1KoHXHHBw/OSh3uafFWCftrnIcnsn/4f2VWgW1554I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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