SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '86d3c9ece46f54271a6b637762d6c4226a0f73da190121936148cd378a571966' 
  AND token = 'VDcGHaXAbSQCPdZIjFFZFhQp+K6/4L/yAJevdnW0Ynw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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