SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '82e1797233cfc41aac10882c8e185d5c073973a8e50c7576147ff1c42bc7db64' 
  AND token = 'TnBwWkPgsVGExL98HW5EQevQjJaxQnLuKjJ9SKeZRqE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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