SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b28dfb06ce4ae19c4492ef9cf25d69135b5250abe4767fe143748984eca71c60' 
  AND token = 'hwt5wLsGENCreNJ+jEzavyv19lj9WxNJoQjVsmlqr5o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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