SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87a6652255e0f0dc5393a1ac7b8d8b5d17d6e8d29a572083c8341759b3c48fc3' 
  AND token = 'wCH1ry2bTzBomLTk1aqunpZ/tUhHYQMQpDK3foiTm+8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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