SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4d6ec014ae68502d3766a5e586689fddfeee2e85a90734f570c15f07fc1c3cc' 
  AND token = 'FLXJt7KHCw+fm6o8tQ4nmbBZP0M/kgXdin9A2qZ/jjc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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