SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78911d4bbad571639256951e0e7cdaa87319ba2ceb1cbfd53f7d6324543d5ddc' 
  AND token = 'w26H+poXKxDY4hDPN5PsCJHXICHqpGoznzQHoY9eh6E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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