SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab389af450d6a73d1848fee2ff676d61537d5f460dd2f06d429f12a69dc1e7ca' 
  AND token = 'smJb+vq4izslc7V5BKDIfEGE+o/lHTh9GfzTfDn29bA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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