SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'debc29953956b6fa1c67b09d5d7b635aaf6f00426ceb26bae69f8eb3d748728d' 
  AND token = 'p/hx4gtePG11hMKQN8uuw4x+AiLENvxMDYBGE+G7QIQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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