SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1d973582497d89f801d2e5de9e885238176cbe219df3d14f0dceb57c428028cd' 
  AND token = 'KoWRANUYo9bfAWK3zifEWYure48dEiRVxip0BimPjS4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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