SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e38b74382cc7938379e65c715f18020cd58f7e651571fa09e1de56c351199bb4' 
  AND token = 'vvaXVSxw6QJGtMOIy2URRn1F0woK4IzI5wZizNuDqHc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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